Comment by _kb

Yes - sector lights. When you are on a channel / in safe water they’re white, red in the port sector, or green when you are too far starboard. Some will combine this with an angle dependant flash to alert you how far into a port or starboard sector you may be.

The other common mark you’ll see are leads which are two lights, one behind the other. The front is lower and the rear is higher. When they’re aligned you’re on the channel. These also have day shapes attached that provide an upwards and downwards facing triangle to align.